yeah, many do run their macbooks from the ac adapter without the battery. i personally do run my macbook from the ac adapter and have the battery installed. once the battery is charged it doesn't chage further, it just stops. but the question i keep asking myself is when you remove the battery. there is no rubber sole on the right hand corner of the macbook to hold it up so won't the mactop always be bobbing around?
thanks in advance

I've always heard that if you leave the charger in after its charged it wears down your battery. I know this was the case for my previous laptop. It was always plugged in and after about a year of doing this its charge without the ac adapter lasted about an hour at most.

I am not sure whether or not the urban legend of leaving the battery in and charged all of the time will cause it to degrade is true or not. I would think that will today's more efficient technologies that even if this were true, the amount of degradation would be negligible.

Personally I would think that even though a battery may show green and be charged, it still has some kind of juice running through it and then into the laptop. How else could one account for the great redundancy of the macbook's (and most laptop systems) ability to have the plug pulled and continue working without so much as a hiccup?

I believe that a battery is in a constant state of discharge no matter what. This occurs whether or not the battery is plugged in or by itself on a table. The addition of heat to a batter, however, increases that rate of discharge, thereby forcing you to charge it sooner than intended. With that in mind, perhaps it is killing the battery at a faster rate to be in the machine charged as opposed to by itself in a cool spot.

EDIT: Sorry, simple answer:

Yes, your battery is discharging constantly, to include while plugged in and "fully charged" in your macbook. Evidence suggests that your battery will wear down less quickly if away from the heat of your machine, but since it isn't a big story all over the computer world I doubt that it's that much of an issue. Your battery's life is primarily decided by how often you cycle it (use the charge, charge it back up).